1. Field of the Invention
The present invention relates to an image sensing apparatus and, in particular, to an image sensing apparatus which is suitable for circuit integration resulting from the digitization of signal processing operations in such an image sensing apparatus.
2. Related Background Art
There have been remarkable developments in the field of image sensing apparatuses, such as video cameras. The performance of such apparatuses has been improved and enhanced in various ways, for example, by equipping them with a number of functions. Further, a digital signal processing operation has recently been introduced into this field.
In this regard, an image sensing apparatus has already been proposed in which an output from an image sensing device such as a two-dimensional CCD having minute color separation filters arranged over the entire surface thereof, is digitized by means of an AD converter, and subjected to a signal processing operation by a signal processing circuit using a digital processing technique, thereby obtaining television signals.
Further, integration of such image sensing apparatuses has been considered.
In the prior-art technique described above, however, the circuits for automatically effecting the focusing, exposure adjustment, white balance adjustment, etc. of the image sensing apparatus are controlled separately through different signal paths by means of a microcomputer, with the result that the construction of the image sensing apparatus as a whole is rather complicated. Further, in the prior-art technique, the number of IC chips used is rather large and, moreover, it is hard to integrate these IC chips. These factors have been a barrier to reducing the size of the image sensing apparatus as a whole. In such an image sensing apparatus, the digital signal processing is separately performed in different sections of the apparatus. Thus, it has been impossible to realize a digital integrated circuit for video cameras which is capable of synthesizing the performance of signal processing operations in a digital video camera.
The present invention has been made with a view toward solving the problems mentioned above. It is a first object of the present invention to provide an image sensing apparatus in which a plurality of signal processing operations in the apparatus are simplified, and in which the number of signal paths is substantially reduced, thereby simplifying the construction of the control system and improving the reliability of the image sensing apparatus.
A second object of the present invention is to provide an image sensing apparatus in which an adjustment on adjusting sections related to an image sensing operation using the output of various adjustment signal generating means in the image sensing apparatus can be performed with substantially simplified signal paths between the adjustment signal generating means and the control means.
To achieve these objects, there is disclosed in accordance with a preferred embodiment of the present invention, an image sensing apparatus comprising:
signal processing means for processing image sensing signals;
a plurality of adjustment signal generating means for generating mutually different signals for automatic adjustment by using part of the signals of the signal processing means;
interface means for inputting the output of the plurality of adjustment signal generating means and outputting it through a common signal path; and
control means for adjusting a plurality of adjusting sections of the image sensing apparatus by using the output of the plurality of adjustment signal generating means output through the common signal path.
A third object of the present invention is to provide an image sensing apparatus in which the signal paths between the control means and a plurality of signal processing blocks for performing various signal processing operations of the image sensing apparatus and the signal processing operations are simplified, thereby making it possible to realize a one-chip-type control circuit for controlling an image sensing operation.
A fourth object of the present invention is to provide an image sensing apparatus in which it is possible to use a semiconductor device of a small mounting area having a substantially reduced number of output terminals, thereby improving the reliability of the image sensing apparatus.
A fifth object of the present invention is to provide an image sensing apparatus in which adjustment of a plurality of adjusting sections of an image sensing apparatus by means of the output of the plurality of adjustment signal generating circuits can be performed with substantially reduced signal paths between a plurality of adjustment signal generating circuits and a control microprocessor, thereby simplifying the circuit construction of the image sensing apparatus as a whole and improving the reliability thereof.
To achieve these objects, there is disclosed in accordance with a preferred embodiment of the present invention, an image sensing apparatus comprising the following components which are integrated on a common semiconductor:
signal processing means for processing image sensing signals;
a plurality of adjustment signal generating means for generating mutually different signals for automatic adjustment by utilizing part of the signals of the signal processing means; and
interface means for inputting the output of the plurality of adjustment signal generating means and outputting it through a common signal path.
A sixth object of the present invention is to provide an image sensing apparatus in which various adjusting circuits of the image sensing apparatus are adapted to perform digital signal processing operations, and in which the control system for these signal processing circuits is simplified, thereby realizing a one-chip microprocessor for image sensing apparatuses.
A seventh object of the present invention is to provide a digital signal processing circuit IC for video cameras in which digital signal processing circuit blocks for automatic focusing, white balance adjustment, and automatic iris adjustment are realized in a one-chip structure.
An eighth object of the present invention is to provide a digital signal processing circuit interface for video cameras in which interface blocks for outputting parameters for performing adjustments regarding an image sensing operation, such as automatic focusing, white balance adjustment and automatic iris adjustment to a common arithmetic circuit are realized in a one-chip structure.
Other objects and features of the present invention will become apparent from the following embodiments and drawings.